Acquisition, placement, and folding of fabric materials

摘要

This paper discusses the technical issues associated with the acquisition, placement, and folding of fabric materials with mechatronic devices and machines. Earlier work in this area considered the acquisition of fabrics from a stack of materials. Numerous techniques were evaluated and suggested as a satisfactory way to provide "pick and placement" of such materials for various automated processes. Several end-effector devices were developed which used "pinching and stretching" and "multiple roller" approach for handling, placing, and smoothing fabrics on a flat surface. Fabric wrinkles were detected using a feedback laser sensor to assist in the placement and positioning of fabrics. Later work focused on the positioning of fabrics that required issues of alignment, placement and folding for a variety of fabric operations. A two-dimensional process considered precise placement, laying down, and then folding of a fabric material to have matched ends using a robot manipulator using visual feedback sensing. Additionally, three-dimensional diagonal folding of fabric was considered based on knowledge developed from the two-dimensional case. Work was also conducted to mathematically model and measure deformations of limp fabrics and how wrinkling influenced the process of fabric smoothing, alignment, and folding. The results of this work showed that different fabric types (lighter versus heavier) have different sensitivities and hysteritic effects with respect to wrinkling, smoothing, alignment, and folding.